The objective is to define the dominant or recessive nature of the neoplastic character of normal cells transformed in vitro by chemical carcinogens and to analyze this trait. APPROACH: Numerous clones of cultured hamster cells transformed by chemical carcinogens will be tested by somatic cell hybridization to determine if their anchorage independent phenotype is dominant or recessive. If dominant, attempts will be made to transfer the phenotype by isolated DNA thus proving it is a true genetic trait. If recessive the number of genes capable of giving rise to transformation will be assessed by complementation analysis.